SN54HC148, SN74HC148
8-LINE TO 3-LINE PRIORITY ENCODERS
SCLS109D – MARCH 1984 – REVISED MAY 1997
operating characteristics, T = 25°C
A
PARAMETER
TEST CONDITIONS
TYP
UNIT
C
Power dissipation capacitance
No load
35
pF
pd
PARAMETER MEASUREMENT INFORMATION
V
CC
From Output
Under Test
Test
Point
Input
50%
50%
0 V
C
= 50 pF
L
t
t
PLH
PHL
90%
(see Note A)
V
V
OH
In-Phase
Output
90%
t
50%
10%
50%
10%
LOAD CIRCUIT
OL
t
r
f
f
t
t
PLH
PHL
90%
V
CC
V
V
90%
t
90%
OH
Input
50%
10%
50%
10%
90%
t
Out-of-Phase
Output
50%
10%
50%
10%
0 V
OL
t
r
f
t
r
VOLTAGE WAVEFORM
INPUT RISE AND FALL TIMES
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT TRANSITION TIMES
NOTES: A.
B. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following
characteristics: PRR ≤ 1 MHz, Z = 50 Ω, t = 6 ns, t = 6 ns.
C includes probe and test-fixture capacitance.
L
O
r
f
C. The outputs are measured one at a time with one input transition per measurement.
D. and t are the same as t
t
.
pd
PLH
PHL
Figure 1. Load Circuit and Voltage Waveforms
6
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